Process for producing polyolefin elastomer employing a metallocene catalyst

ABSTRACT

A liquid phase polymerization process is provided for producing a polyolefin elastomer, e.g., one derived from ethylene, another α-olefin such as propylene and optionally, a diene, employing a metallocene catalyst. The process comprises contacting monomer under liquid phase polymerization conditions with a catalyst composition obtained by combining (a) a metallocene procatalyst, preferably one containing a bridging group possessing at least two bulky groups, and (b) a cocatalyst such as aluminoxane, preferably a cation-generating cocatalyst, in partial or total replacement of aluminoxane.

BACKGROUND OF THE INVENTION

1. Field of the Invention

This invention relates to a liquid phase polymerization process forproducing a polyolefin elastomer, e.g., one derived from ethylene,another α-olefin such as propylene and, optionally, a diene, to acation-generating cocatalyst for activating a metallocene procatalystthat can be employed in the polymerization process, to the resultingpolyolefin elastomer possessing a desirably high molecular weight(M_(w)), high Mooney viscosity (ML₁₊₄ at 125° C.), low polydispersityindex (M_(w)/M_(n)), low glass transition temperature (T_(g)) and lowhysteresis (tan δ) and to various products manufactured therefromincluding rubber articles such as hoses, belts and moldings, polymerblends containing one or more other hydrocarbon polymers and lubricatingoils in which the elastomer functions as a viscosity modifier.

2. Description of the Prior Art

The most common polyolefin elastomers produced today are copolymers ofethylene and propylene (EP) and terpolymers of ethylene, propylene and adiene (EPDM). Ordinary EP elastomers can be cured using such curativesas organic peroxides, while the use of sulfur as a curative requires theincorporation of a diene. EPDM elastomers are usually produced withvanadium-organoaluminum catalysts, i.e., Ziegler-Natta catalysts.

Along with the better known EP and EPDM polymers, co- and terpolymersincorporating other α-olefins in place of propylene such as 1-butene,1-pentene, 1-hexene, styrene, and combinations thereof are also known.EPDMs are representative of the more general category ofethylene-α-olefin diene elastomers (EODEs). Of the EODEs, EPDMs haveachieved particular prominence due to the many properties which makethem desirable for applications requiring good weather and acidresistance and high and low temperature performance. Notableapplications of the EPDMs include their use in such products as hoses,gaskets, power transmission belts, conveyor belts, bumpers, automotiveextrusions and moldings, weather stripping, blending components forplastics and rubbers such as polypropylene, polystyrene and butylrubber, fabric coatings, viscosity modifiers for lubrication oils, tiresidewalls and in roofing and other membrane applications, shoe soles andheels and many other rubber articles. Another noteworthy application ofthe EPDMs is in wire and cable insulation due to their excellentdielectric properties.

It is desirable for an EPDM to have a reasonably fast cure rate and highstate of cure, requirements calling for a relatively high diene content,e.g., three percent or higher. The cure rate for an EPDM elastomer andthe final properties of the cured article depend upon the type of dieneincorporated. For example, on a comparable diene weight percent basis,an EPDM produced with 5-ethylidiene-2-norbornene (ENB) as the diene willhave a faster cure rate using a sulfur cure than would an EPDMcontaining dicyclopentadiene (DCPD) or 1,4-hexadiene (HD).

As for the properties of cured EPDM, EPDMs made with hexadiene as thetermonomer are known to exhibit good heat resistance. For mostcommercial elastomer applications, the EPDM should have a weight-averagemolecular weight (M_(w)) of at least about 300,000, or ML₁₊₄ at 125° C.of at least about 20 when expressed in terms of Mooney viscosity. Inmany applications, it is further desirable that the molecular weightdistribution (MWD) of an EPDM be characterized by a ratio of weightaverage molecular weight to number average molecular weight(M_(w)/M_(n)), i.e., polydispersity index, of not greater than about 7and preferably not greater than about 5.

The properties of an EPDM elastomer such as its tensile strength,processability and tack can be related to its degree of crystallinity.Since in most commercial uses elastomers are higher in molecular weightthan plastics, too high a degree of crystallinity can make an EPDMdifficult to process at ordinary temperatures. Although good physicalproperties are desirable, especially in such applications as hose,tubing, wire and cable, excessive crystallinity can cause an EPDM toexhibit high hardness and stiffness resulting in a “plastic” rather thana “rubber” surface with poor surface tack.

In general, commercially useful plastics, which are homo- and copolymersof ethylene, propylene, and higher α-olefins, need not have as high amolecular weight as commercially useful elastomers of ethylene-α-olefinssuch as EPDM. In terms of the catalysts used for each, when producingcopolymers with compositions of M_(w) in the elastomer range, catalyststhat provide high M_(w) plastic copolymers may produce low M_(w)polymers unsuitable for elastomer applications. Similarly, undesirableMWD changes can occur or the compositional distribution can change.Thus, catalyst performance for the production of plastics is notindicative of catalyst performance for the production of elastomers.

In most current EPDM production, the catalysts conventionally employedin the production of high molecular weight EPDM elastomers are solublevanadium catalysts such as VCl₄, VOCl₃, VO(Ac)₃ or VO(OR)₃ where R is analkyl group together with an organoaluminum compound. The activity ofthe vanadium catalysts are relatively low, e.g., producing 5-20 kgpolymer/g vanadium.

In current commercial grades of EPDM, crystallinity is a function ofboth the ethylene content of the polymer and the catalyst system usedfor its production. For a given polymer composition, the catalyst systemcontrols the fraction of ethylene units present in long ethylenesequences which are capable of crystallizing. With any given catalystand reactor configuration, polymers with higher ethylene content willhave longer ethylene sequences and be more crystalline.

In current EPDM production based on vanadium catalysts, the product EPDMpolymers are completely amorphous (non-crystalline) at ethylene contentsbelow about 55 wt %. Conversely, at ethylene contents of about 55 wt %or greater, an EPDM will possess significant crystallinity. The degreeof crystallinity depends less on the diene content of the EPDM than onthe percentage of ethylene.

In order for the catalyst system to be useful for the commercialproduction of an EPDM elastomer, it is desirable for the crystallinityof the polymer to be roughly comparable to that of currently availablecommercial grades of EPDM for most applications.

Metallocene catalysts typically consist of a transition-metal atomsandwiched between ring structures to form a sterically hindered site.Plastics obtained with metallocene catalysts tend to have increasedimpact strength and toughness, good melt characteristics, and improvedclarity in films.

In actual practice, the extent to which metallocene catalysts caneffectively replace traditional catalysts in polymer production dependson the cost and efficiency of the system. Metallocene catalysts costsignificantly more than the traditional Ziegler-Natta catalysts but themetallocene systems are considerably more productive. In some cases, theincreased productivity of metallocene catalysts relative to theZiegler-Natta catalysts ranges from one to two orders of magnitude morepolymer produced per pound of catalyst.

Since the recent introduction of aluminoxane-activated metallocenecatalysts for the production of polyethylene, polypropylene, andcopolymers of ethylene and α-olefins such as linear low densitypolyethylene (LLDPE), some effort has been made to apply these catalyststo the production of EPDM elastomers. For this use, it is desired thatthe catalyst produce high yields of EPDM in a reasonable polymerizationtime, result in adequate incorporation of the diene monomer(s) andprovide a random distribution of monomers while enabling good control ofM_(w) over a wide range while yielding a relatively narrow MWD.

Kaminsky et al., J. Poly. Sc., Vol., 23, 2151-2164 (1985), discloses theuse of a metallocene-methylaluminoxane (MAO) catalyst system to producelow molecular weight EPDM elastomers, i.e., M_(w)s of not greater thanabout 150,000. Such catalysts require long reaction times and providelow yields and are therefore impractical for commercial EPDMmanufacture. Similarly, Japanese Patent 62-121, 771 describes ametallocene-catalyzed polymerization process yielding anethylene-1-butene-diene elastomer of high ethylene content in low yield.

Other polymerization processes for producing EPDMs featuring the use ofa metallocene catalyst activated by an aluminoxane such as MAO aredescribed, e.g., in U.S. Pat. Nos. 4,871,705, 5,001,205, 5,229,478 and5,442,020, EP 347,129 and WO 95/16716. As discussed more fully below,the lack of more widespread commercial implementation of metallocenecatalysts where the production of high molecular weight elastomers isconcerned is due at least in part to the need to use very large amountsof aluminoxane cocatalyst to activate the metallocene to acceptablelevels.

EPA 593,083 describes a gas phase polymerization process for producingEPDM employing a bridged metallocene catalyst (1):

Gas phase polymerization, however, is prone to a number of technicaldifficulties, reactor fouling among them, that need to be overcomebefore this type of process for producing EPDM elastomers will achievegeneral acceptance by the industry.

EPA 612,769 and EP 653,445 both disclose the use of metallocene catalyst(1) in a solution phase polymerization process for producing linear low[molecular weight] propylene-diene elastomer (LLPDE) in contrast to ahigh molecular weight elastomer that is an object of the presentinvention.

U.S. Pat. No. 5,401,817 describes a polymerization process employingbridged metallocene catalyst (2):

There is, however, no mention of producing an elastomer in this patent.

Green et al., J. Chem. Soc. Dalton Trans., 657-665 (1994) describes thepolymerization of propylene and styrene employing a bridged metallocenecatalyst (3):

No mention of producing an elastomer is made in this publication.

Kaminsky et al., Angew. Chem. Int. Ed. Engl., 34, 2273-2275 (1995)describes bridged metallocene catalyst (4), together with MAO, for thecopolymerization of ethylene with bulky cycloalkenes:

Another aspect of the present invention lies in the discovery that notall bridged metallocene catalysts will provide high molecular weightelastomers. Thus, e.g., it has been found that bridged metallocenecatalyst (5)

which differs from metallocenes (1)-(4), supra, only in the nature ofthe bridging group joining the two cyclopentadienyl-derived ligandsprovides low molecular weight (<50,000) ethylene-propylene copolymers.In contrast to this result and as discovered herein, activatedmetallocene catalyst (1) provides elastomers of high molecular weight(>300,000).

Bridged metallocene catalysts (6) and (7) possessing the bis(indenyl)and the bis(fluorenyl) structures, respectively, are capable ofproviding high molecular weight amorphous ethylene-propylene copolymers:

Metallocenes (6) and (7) are described in U.S. Pat. No. 5,145,819(indenyl) and U.S. Pat. No. 5,436,305 (fluorenyl) for the production ofhomopolymers. No mention is made in either patent of employing thedisclosed metallocene for the production of an EPDM-type elastomer.

As previously mentioned, it has been discovered that one of theobstacles to widespread commercial implementation of metallocenecatalysis lies in the use of an aluminoxane as cocatalyst. Aluminoxanesare expensive and large amounts are required in order to activate themetallocene catalyst with which they are associated.

SUMMARY OF THE INVENTION

It is an object of the present invention to provide a liquid phasepolymerization process, i.e., one carried out under solution or slurryconditions and in batch or continuously, for producing a polyolefinelastomer employing as the catalyst composition an activated bridgedmetallocene in which the bridging group possesses at least two bulkygroups.

It is a further object of the invention to provide such a process forthe polymerization of olefins to provide high molecular weight EP andEODEs such as the EPDMs.

Yet another object of the invention is to provide a catalytically activecomposition comprising a metallocene procatalyst activated by aparticular type of cation-generating cocatalyst.

Additional objects of the invention include providing a polyolefinelastomer possessing a combination of high molecular weight, high Mooneyviscosity, low polydispersity index, low glass transition temperatureand low hysteresis and various products manufactured therefrom.

In keeping with these and other objects of the invention, there isprovided a process for the liquid phase polymerization of ethylene, atleast one other α-olefin and, optionally, at least one diene monomer toprovide an elastomer, the process comprising contacting the monomerunder liquid phase polymerization conditions with a catalyticallyeffective amount of a catalyst composition comprising the productobtained by combining (a) a metallocene procatalyst, preferably onecontaining a bridging group possessing at least two bulky groups, and(b) a cocatalyst, preferably a cation-generating cocatalyst ashereinafter described.

The polyolefin elastomers obtained by the process of this invention arethemselves novel, possessing, in combination, a higher molecular weight(M_(w)), higher Mooney viscosity (ML₁₊₄ at 125° C.) a lowerpolydispersity index (M_(w)/M_(n)), a lower glass transition temperature(T_(g)) and a lower hysteresis (tan δ) than these same properties inknown polyolefin elastomers incorporating equivalent amounts of the sameolefins. These elastomers confer advantageous properties on productsmanufactured therefrom relative to the same products manufactured fromknown elastomers.

The terms “metallocene” and “metallocene procatalyst” as used hereinshall be understood to refer to compounds possessing a transition metalM, at least one non-cyclopentadienyl-derived ligand X and zero or oneheteroatom-containing ligand Y, the ligands being coordinated to M andcorresponding in number to the valence thereof. Such compounds,cocatalysts useful for their activation to provide metallocene catalyststhat may be employed for the polymerization of olefins to providepolyolefin homopolymers and copolymers and/or polymerization processesemploying one or more of the metallocene catalysts are described in,among others, U.S. Pat. Nos. 4,752,597; 4,892,851; 4,931,417; 4,931,517;4,933,403; 5,001,205; 5,017,714; 5,026,798; 5,034,549; 5,036,034;5,055,438; 5,064,802; 5,086,134; 5,087,677; 5,126,301; 5,126,303;5,132,262; 5,132,380; 5,132,381; 5,145,819; 5,153,157; 5,155,080;5,225,501; 5,227,478; 5,229,478; 5,241,025; 5,243,002; 5,278,119;5,278,265; 5,281,679; 5,296,434; 5,304,614; 5,308,817; 5,324,800;5,328,969; 5,329,031; 5,330,948; 5,331,057; 5,349,032; 5,372,980;5,374,753; 5,385,877; 5,391,629; 5,391,789; 5,399,636; 5,401,817;5,406,013; 5,416,177; 5,416,178; 5,416,228; 5,427,991; 5,439,994;5,441,920; 5,442,020; 5,449,651; 5,453,410; 5,455,365; 5,455,366;5,459,117; 5,466,649; 5,470,811; 5,470,927; 5,477,895; 5,491,205; and,5,491,207, the contents of which are incorporated by reference herein.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a graphical comparison of the stability of a metalloceneprocatalyst activated by cation-generating cocatalysts both within(Example 21) and outside (Comparative Example 30) the scope of theinvention, the stability of the catalysts being shown as the amount ofmonomer consumed over time.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The polymerization process herein employs a catalyst compositionobtained by activating a metallocene procatalyst with a suitablecocatalyst.

The metallocene procatalyst is preferably one or a mixture ofmetallocene compounds of either or both of the following generalformulae:

(Cp¹R¹ _(m))R³ _(n)(Cp²R² _(p))MX_(q)  (I)

(Cp¹R¹ _(m))R³ _(n)Y_(r)MX_(s)  (II)

wherein Cp¹ of ligand (Cp¹R¹ _(m)) and Cp² of ligand (Cp²R² _(p)) arethe same or different cyclopentadienyl rings, R¹ and R² each is,independently, halogen or a hydrocarbyl, halocarbyl,hydrocarbyl-substituted organometalloid or halocarbyl-substitutedorganometalloid group containing up to about 20 carbon atoms, m is 0 to5, p is 0 to 5 and two R¹ and/or R² substituents on adjacent carbonatoms of the cyclopentadienyl ring associated therewith can be joinedtogether to form a ring containing from 4 to about 20 carbon atoms, R³is a bridging group, n is 0 or 1, Y is a heteroatom-containing ligand inwhich the heteroatom is coordinated to M, M is a transition metal havinga valence of from 3 to 6, each X is a non-cyclopentadienyl ligand andis, independently, halogen or a hydrocarbyl, oxyhydrocarbyl, halocarbyl,hydrocarbyl-substituted organometalloid, oxyhydrocarbyl-substitutedorganometalloid or halocarbyl-substituted organometalloid groupcontaining up to about 20 carbon atoms, q is equal to the valence of Mminus 2, r has the value of n and s is equal to the valence of M minus 1when r is 0 and is equal to the valence of M minus 2 when r is 1.

Methods for preparing these and other useful metallocene procatalystsare known in the art and do not constitute a part of the presentinvention.

Metallocene procatalyst (I) can be activated either with an aluminoxaneor, preferably, with the cation-generating cocatalyst hereinafterdescribed. If the metallocene procatalyst is entirely one of formula(II), it is activated with the aforementioned cation-generatingcocatalyst. However, where the metallocene procatalyst is one of formula(I) and the cocatalyst is entirely an aluminoxane, ligand (Cp¹R¹ _(m))must be different from ligand (Cp²R² _(p)), bridging group R³ mustcontain at least two bulky groups and the value of n must be 1. Of thesebridged metallocenes, it is preferred that bridging group R³ possess thestructure

in which bulky groups R⁴ and R⁵ each, independently, is, or contains, acyclohydrocarbyl group containing up to about 20, and preferably from 6to about 12, carbon atoms and from 0 to 3 heteroatoms such as oxygen,sulfur, tertiary nitrogen, boron or phosphorus and, in particular, is acycloalkyl, heterocycloalkyl, cycloalkenyl, heterocycloalkenyl, aryl,heteroaryl, alkaryl, alkylheteroaryl, aralkyl, heteroaralkyl, and soforth, M is titanium, zirconium or hafnium, q is 2 and each X ishalogen.

Of this preferred group of bridged metallocenes, those in which ligand(Cp¹R_(m) ¹) is unsubstituted cyclopentadienyl, ligand (Cp²R_(p) ²) isindenyl or fluorenyl, M is zirconium, R⁴ and R⁵ each is phenyl and eachX ligand is chlorine are still more preferred. These more preferredmetallocenes correspond to known metallocene compounds (1)-(4), supra.

Still other preferred bridged metallocenes (I) that can be used in thepolymerization process of this invention include:

diphenylmethylene(indenyl)(fluorenyl)zirconium dichloride,

diphenylmethylene(cyclopentadienyl)(4,5,6,7-tetrahydroindenyl)zirconiumdichloride,

diphenylmethylene(cyclopentadienyl)(2-methylindenyl) zirconiumdichloride,

diphenylmethylene(2,4-dimethylcyclo-pentadienyl)(3′,5′-dimethylcyclopentadienyl)zirconiumdichloride,

diphenylmethylene(2-methyl-4-tert-butylcyclo-pentadienyl)(3′-tert-butyl-5′-methylcyclopentadienyl)zirconium dichloride,

dixylylmethylene(2,3,5-trimethylcyclopentadienyl)(2′,4′,5′-trimethylcyclopentadienyl)zirconium dichloride,

dixylylmethylene(2,4-dimethylcyclopentadienyl)(3′,5′-dimethylcyclopentadienyl)zirconiumdichloride,

dixylylmethylene(2-methyl-4-tert-butylcyclopentadienyl)(3′-tert-butyl-5-methylcyclopentadienyl)zirconium dichloride,

dixylylmethylene(cyclopentadienyl)(fluorenyl)zirconium dichloride,

di-o-tolylmethylene(cyclopentadienyl)(3,4-dimethylcyclopentadienyl)zirconiumdichloride,

di-o-tolylmethylene(cyclopentadienyl)(3,4-dimethylcyclopentadienyl)zirconiumdichloride,

di-o-tolylmethylene(cyclopentadienyl)(3,4-dimethylcyclopentadienyl)zirconiumdichloride,

di-o-tolylmethylene(cyclopentadienyl)(indenyl)zirconium dichloride,

dibenzylmethylene(cyclopentadienyl)(tetramethylcyclopentadienyl)zirconiumdichloride,

dibenzylmethylene(cyclopentadienyl)(indenyl)zirconium dichloride,

dibenzylmethylene(cyclopentadienyl)(fluorenyl)zirconium dichloride,

dicyclohexylmethylene(cyclopentadienyl)(indenyl)zirconium dichloride,

dicyclohexyl(cyclopentadienyl)(fluorenyl)zirconium dichloride,

dicyclohexylmethylene(2-methylcyclopentadienyl)(fluorenyl) zirconiumdichloride,

diphenylsilyl(2,4-dimethylcyclopentadienyl)(3′,5′-dimethylcyclopentadienyl)zirconiumdichloride,

diphenylsilyl(2,4-dimethylcyclopentadienyl)(3′,5′-dimethylcyclopentadienyl)zirconiumdichloride,

diphenylsilyl(2,3,5-trimethylcyclopentadienyl)(2,4,5-trimethylcyclopentadienyl)zirconiumdichloride,

tetraphenyldisilyl(cyclopentadienyl)(indenyl)zirconium dichloride,

tetraphenyldisilyl(3-methylcyclopentadienyl)(indenyl) zirconiumdichloride,

tetraphenyldisilyl(cyclopentadienyl)(fluorenyl)zirconium dichloride,

di-o-tolylsilyl(cyclopentadienyl)(trimethylcyclopentadienyl) zirconiumdichloride,

di-o-tolylmethylene(cyclopentadienyl)(3,4-dimethyl-cyclopentadienyl)zirconiumdichloride,

di-o-tolylmethylene(cyclopentadienyl)(3,4-dimethyl-cyclopentadienyl)zirconiumdichloride,

di-o-tolylmethylene(cyclopentadienyl)(3,4-dimethylcyclopentadienyl)zirconiumdichloride,

di-o-tolylmethylene(cyclopentadienyl)(indenyl)zirconium dichloride,

dibenzylmethylene(cyclopentadienyl)(tetramethylcyclopentadienyl)zirconiumdichloride,

dibenzylmethylene(cyclopentadienyl)(indenyl)zirconium dichloride,

dibenzylmethylene(cyclopentadienyl)(fluorenyl)zirconium dichloride,

dicyclohexylmethylene(cyclopentadienyl)(indenyl)zirconium dichloride,

dicyclohexyl(cyclopentadienyl)(fluorenyl)zirconium dichloride,

dicyclohexylmethylene(2-methylcyclopentadienyl)(fluorenyl) zirconiumdichloride,

diphenylsilyl(2,4-dimethylcyclopentadienyl)(3′,5′-dimethylcyclopentadienyl)zirconiumdichloride,

diphenylsilyl(2,4-dimethylcyclopentadienyl)(3′,5′-dimethylcyclopentadienyl)zirconiumdichloride,

diphenylsilyl(2,3,5-trimethylcyclopentadienyl)(2,4,5-trimethylcyclopentadienyl)zirconiumdichloride,

tetraphenyldisilyl(cyclopentadienyl)(indenyl)zirconium dichloride,

tetraphenyldisilyl(3-methylcyclopentadienyl)(indenyl) zirconiumdichloride,

tetraphenyldisilyl(cyclopentadienyl)(fluorenyl)zirconium dichloride,

di-o-tolylsilyl(cyclopentadienyl)(trimethylcyclopentadienyl) zirconiumdichloride,

di-o-tolylsilyl(cyclopentadienyl)(tetramethylcyclopentadienyl)zirconiumdichloride,

di-o-tolylsilyl(cyclopentadienyl)(3,4-diethylcyclopentadienyl)zirconiumdichloride,

di-o-tolysilyl(cyclopentadienyl)(triethylcyclopentadienyl)zirconiumdichloride,

dibenzylsilyl(cyclopentadienyl)(fluorenyl)zirconium dichloride,

dibenzylsilyl(cyclopentadienyl)(2,7-di-t-butylfluorenyl)zirconiumdichloride, and

dicyclohexylsilyl(cyclopentadienyl)(flurorenyl)zirconium dichloride.

In the preferred metallocene procatalysts of formula (II), n and r areboth 1, the valence of M is 4, X is halogen and s is 2. Illustrative ofsuch preferred metallocene procatalysts (II) that can be activated bythe cation-generating cocatalyst of this invention are the following:

dimethylsilyl(tetramethylcyclopentadienyl)(cyclohexylamido) zirconiumdichloride,

dimethylsilyl(3,4-dimethyl cyclopentadienyl)(cyclohexylamido)hafniumdichloride,

dimethylsilyl(tetramethylcyclopentadienyl)(butylamido)titaniumdichloride,

dimethylsilyl(3,4-di-t-butylcyclopentadienyl)(cyclododecylamido)titaniumdichloride,

dimethylsilyl(2,5-dimethylcyclopentadienyl)(cyclododecylamido)titaniumdichloride,

di-n-propylsilyl(2,5-dimethylcyclopentadienyl)(p-n-butylphenylamido)titaniumdichloride,

di-isopropylsilyl(2-indenyl)(cyclohexylamido)zirconium dihalide,

diphenylsilyl(tetra-n-propylcyclopentadienyl)(isopropylamido)zirconiumdihalide, and

dimethylmethylene(2-methyl-5-t-butylcyclopentadienyl)(dimethylamido)zirconium dihalide.

The cocatalyst, or activator, employed with the preferred bridgedmetallocene procatalysts of formula (I) can, as previously stated, beany of the aluminoxanes known to activate metallocene procatalysts. Forfurther details of the aluminoxane cocatalysts including suchalkylaluminoxanes as MAO see, e.g., U.S. Pat. No. 5,229,478. In general,the bridged metallocene procatalyst can be present in the reactor in anamount, expressed in terms of its transition metal content, of fromabout 0.0001 to about 0.02, preferably from about 0.0002 to about 0.015and more preferably from about 0.0002 to about 0.01, millimoles/liter.Corresponding to these amounts of transition metal, the aluminoxanecocatalyst can be utilized in an amount of from about 0.01 to about 100,preferably from about 0.02 to about 75 and more preferably from about0.025 to about 50, millimoles/liter. It will, of course, be recognizedthat optimum levels of bridged metallocene procatalyst and aluminoxanecocatalyst will to some extent depend upon the specific procatalyst andcocatalyst selected as well as other polymerization process variables.

When employing an aluminoxane cocatalyst, it can be advantageous toinclude a trialkylaluminum such as trimethylaluminum, triethylaluminum,tri(n-propyl)aluminum, triisopropyaluminum, tri(n-butyl)aluminum,triisobutylaluminum, and the like, to reduce the amount of aluminoxanerequired for suitable activation of the metallocene procatalyst. Ingeneral, the optional trialkylaluminum can be utilized in a molar ratioto metallocene procatalyst of from about 1 to about 1000 and preferablyfrom about 2 to about 500.

Preferably, however, the cation-generating cocatalyst of the compositiondescribed below is used to activate metallocene procatalysts (I) and(II). This preferred cocatalyst can be used as a partial or completereplacement for the aluminoxanes, not only for the preferred bridgedmetallocenes described above, but for any of the metalloceneprocatalysts, whether bridged or nonbridged, with which the invention isconcerned. More particularly, the cation-generating cocatalyst hereincomprises: as a first component, a metal- and/or metalloid-containingcompound capable of exchanging at least one X ligand in the metalloceneprocatalyst up to the total number thereof with, independently, ahydrogen atom or a carbohydryl group containing up to about 20 carbonatoms or oxycarbohydryl group containing up to 20 carbon atoms; as asecond component, a neutral metal- and/or metalloid-containing compoundhaving at least one aryl group possessing at least oneelectron-withdrawing substituent; and, as a third component an anionicmetal- and/or metalloid-containing compound having at least one arylgroup possessing at least one electron-withdrawing substituent.

Activation of the metallocene procatalyst can be achieved by combiningthe metallocene with the aforementioned components of thecation-generating cocatalyst either simultaneously or in any sequenceand with any interval of time therebetween. For reasons discussed below,in situ activation of the procatalyst, i.e., within the polymerizationreactor in the presence of monomer, is preferred. However, it is alsowithin the scope of the invention to achieve activation of theprocatalyst in other ways, for example, by reacting the metalloceneprocatalyst with the first component of the cocatalyst and thereaftercombining the product of this reaction with the second and thirdcomponents of the cocatalyst either simultaneously or sequentiallyeither within, or in the absence of, the olefin monomer. In general, themolar ratio of the first component of the cocatalyst to metalloceneprocatalyst can vary from 1 to about 500 and preferably from about 2 toabout 500 and the molar ratios of the second and third components of thecocatalyst to metallocene procatalyst can, independently, vary fromabout 0.5 to about 10 and preferably from about 0.8 to about 5.

The metal- or metalloid-containing first component for providing thecation-generating cocatalyst herein can advantageously be an aluminumcompound of the general formula AlR⁴R⁵R⁶ in which R⁴, R⁵ and R⁶ each,independently, is a hydrocarbyl, e.g., alkyl, or oxyhydrocarbyl, e.g.,alkoxy, group containing up to about 20 carbon atoms, or hydrogen,provided that no more than two of R⁴, R⁵ and R⁶ can be hydrogen.Suitable aluminum compounds include trimethylaluminum, triethylaluminum,tri(n-propyl)aluminum, triisopropylaluminum, tri(n-butyl)aluminum,tri(n-propyl) aluminum, triisobutylaluminum, tri(n-hexyl)aluminum,tri(n-octyl)aluminum, dimethyaluminum hydride, diethylaluminum hydride,diisopropylaluminum hydride, di(n-propyl)aluminum hydride,diisobutylaluminum hydride, di(n-butyl)aluminum hydride,dimethylaluminum ethoxide, di(n-propyl)aluminum ethoxide,diisobutylaluminum ethoxide, di(n-butyl)aluminum ethoxide, and the like.Of the foregoing aluminum compounds, the trialkylaluminums are preferredand of these, triethylaluminum and triisobutylaluminum are morepreferred. Additional representatives of compounds that can be used asthe first component of the cocatalyst are alkali metal organometallics,alkaline earth organometallics and organometal halides (e.g., Grignardreagents), hydrocarbyl complexes of such metals and organometalloidssuch as those of boron, zinc, gallium, germanium, arsenic, telluriummercury, lead, and the like.

Useful second components for providing the preferred cocatalysts includeboranes such as tris(pentafluorophenyl)borane,tris(methoxyphenyl)borane, tris(trifluoromethyl-phenyl)borane,tris(3,5-di[trifluoromethyl]phenyl)borane, tris(tetrafluoroxylyl)borane,tris(tetrafluoro-o-tolyl)borane, and the like. Of the foregoing boranes,tris(pentafluorophenyl)borane andtris(3,5-di[trifluoromethyl]phenyl)borane are preferred. Other usefulsecond components include aluminum homologues of the foregoingcompounds.

Specific third components that can be used in the preferred cocatalystsinclude borates such as lithium tetrakis(pentafluorophenyl)borate,lithium tetrakis(tri-fluoromethylphenyl)borate, lithiumtetrakis(3,5-di[tri-fluoromethyl]phenyl)borate, sodiumtetrakis(pentafluorophenyl)borate, potassiumtetrakis(pentafluorophenyl)borate, magnesiumtetrakis(pentafluorophenyl)borate, titaniumtetrakis(pentafluorophenyl)borate, tintetrakis(pentafluorophenyl)borate, and the like. Of the foregoingborates, alkali metal borates such as lithiumtetrakis(pentafluorophenyl) borate and lithiumtetrakis(3,5-di[trifluoromethyl]phenyl)borate are preferred. Otheruseful third components include aluminate homologues of the foregoingcompounds.

The activated metallocene catalyst composition can be prepared inadvance and thereafter introduced into the polymerization reactor.However, when employing the preferred cation-generating cocatalyst,supra, it is highly preferred to activate the metallocene procatalystwith the cocatalyst components in situ, which is to say, in the presenceof monomer. There are considerable advantages to such in situactivation.

The metallocene procatalysts in which each X ligand is a halogen arefairly stable compounds and impose no special handling or storagerequirements. However, the metallocenes in which one or more X ligandsis a hydrogen atom or a hydrocarbyl group are highly susceptible todegradation when exposed to oxygen, moisture, light and/or heat. Whenprepared in advance, care must be taken to store these metallocenes in amanner which will exclude all of these conditions. This is especiallythe case with the metallocene hydrides which are extremely unstable. Forthese reasons, it is preferred to activate the metallocene procatalystwith the preferred cocatalyst within the polymerization reactor in thepresence of monomer. Activating the procatalyst in this way avoids orgreatly diminishes the possibility of forming catalytically inactivedegradation products.

There are still other significant advantages to in situ activation ofthe metallocene procatalyst. Thus, in situ activation offers theflexibility of adjusting the quantity of aluminum component in thecocatalyst to compensate for process conditions in the polymerizationreactor, e.g., via reactive scavenging of polar impurities. Use ofpreformed metallocene hydrides, hydrocarbyls or oxyhydrocarbyls wouldnecessitate an independent feed of such a scavenger such representing acomplication of the polymerization process. In addition, it has beenobserved herein that activation in the presence of olefin monomerresults in significantly higher initial polymerization activity than thesame catalyst activated in advance of its introduction into thepolymerization reactor.

The α-olefins suitable for use in the preparation of the elastomersherein contain from 3 to about 20 carbon atoms and include propylene,1-butene, 3-methylbutene, 1-pentene, 4-methyl-1-pentene, 1-hexene,1-octene, 1-decene, 1-dodecene, and vinyl aromatic monomers such asstyrene, α-methyl styrene and the like, with propylene being theα-olefin of choice.

The optional diene monomer(s) can be conjugated or nonconjugated.Conjugated monomers include butadiene, isoprene, 2,3-dimethylbutadieneand cyclopentadiene.

Examples of suitable nonconjugated dienes include straight chain acyclicdienes such as 1,4-hexadiene, 1,5-hexadiene, 1,6-heptadiene, and,1,7-octadiene; branched chain acyclic dienes such as4-methyl-l,5-hexadiene, 5-methyl-1,4-hexadiene,3,7-dimethyl-1,6-octadiene, 3-7-dimethyl-1,7-octadiene and mixed isomersof dihydromyrcene and dihydroocinene; unsubstituted and substitutedcyclic dienes such as 1,4-cyclohexadiene, 1,5-cyclooctadiene and1,5-cyclododecadiene; and, multicyclic dienes such as tetrahydroindene,methyltetrahydroindene, dicyclopentadiene;bicyclo-(2,2,1)-hepta-2,6-diene; alkenyl, alkylidene, cycloalkenyl andcycloalkylidene norbonenes such as 5-methylene-2-norbornene,5-ethylidene-2-norbornene, 5-propenyl-2-norbornene,5-isopropylidene-2-norbornene, 5-butenyl-2-norbornene,5-(4-cyclopentenyl)-2-norbornene, 5-cyclohexylidene-2-norbornene,5-vinyl-2-norbornene and norbornadiene. Of the dienes typically used toprepare EODEs, the preferred ones are 1,4-hexadiene,5-ethylidene-2-norbornene, 5-vinylidene-2-norbornene,5-methylene-2-norbornene and dicyclopentadiene and of these,5-ethylidene-2-norbornene, 1,4-hexadiene and dicyclopentadiene are morepreferred.

When employing a diene that results in little if any branching in theproduct elastomer, e.g., such dienes as 1,4-hexadiene,ethylidene-2-norbornene, dicyclopentadiene, 1-methylcyclopentadiene,indene, and the like, it can be advantageous to the properties of theproduct elastomer to include within the monomer mixture a diene thatprovides branching. Branching dienes, as they may be called, includebranched or unbranched acyclic dienes such as 1,5-hexadiene,1,7-octadiene or 4-methyl-i,5-hexadiene; substituted or unsubstitutedcyclic dienes such as cyclopentadiene, 3-methyl-1,4-cyclopentadiene,vinyl cyclohexene or norbornadiene; alkenyl-substituted norbornenes suchas 5-methylene-2-norbornene, 5-vinyl-2-norbornene,5-propenyl-2-norbornene or 5-butenyl-2-norbornene; conjugated acyclicdienes such as butadiene, isoprene or 2,3-dimethylbutadiene; and,dialkenylaromatic dienes such as divinylbenzene.

The preferred elastomeric ethylene-α-olefin copolymers and EODEs cancontain up to about 90, preferably from about 30 to about 85, and morepreferably from about 35 to about 80, weight percent ethylene, thebalance being α-olefin(s) and optional diene monomer(s). The dienemonomer(s), when utilized, can be incorporated into the EODE at a levelof from about 0.1 to about 30, preferably from about 1 to about 25, andmore preferably from about 1 to about 20, weight percent.

Polymerization of the aforementioned monomers using the catalyst of thepresent invention is carried out in the liquid phase, i.e., in asolution or slurry process, either continuously or in batch. Theseprocesses are generally carried out at temperatures in the range of fromabout −20° C. to about 300° C. and preferably from about 0° C. to about200° C., and pressures from about 5 to about 2000 psig. Dilutionsolvents that can be employed include straight and branched chainhydrocarbons such as the butanes, the pentanes, the hexanes, theheptanes, the octanes, and the like, cyclic and alicyclic hydrocarbonssuch as cyclopentane, cyclohexane, cycloheptane, methylcyclopentane,methylcyclohexane, methylcycloheptane and the like, andalkyl-substituted aromatic compounds such as toluene, xylene, and thelike.

A typical batch solution polymerization process can be carried out byfirst introducing the hydrocarbon solvent, e.g., cyclohexane, into astirred tank reactor. The monomer feed comprising ethylene, α-olefin,e.g., propylene, and diene(s) (if utilized) is then sparged into theliquid phase. A hydrocarbon solution of the cocatalyst followed by ahydrocarbon solution of the metallocene procatalyst in the requiredamounts are then added to the liquid phase in the reactor. The rate ofpolymerization is controlled by the concentration of the catalyst. Thereactor temperature is controlled by means of cooling coils, etc., andthe initial total pressure in the reactor is maintained by a constantflow of gaseous monomer(s). By maintaining a faster rate of flow ofgas(es) through the reactor than the rate of polymerization, theconditions in the reactor will approximate steady state conditions. Theethylene content of the elastomer product is determined by themetallocene catalyst used and by the ratio of ethylene to δ-olefin inthe reactor which is controlled by manipulating the relative feed ratesof these monomers to the reactor. After polymerization and deactivationof the catalyst followed by coagulation of the elastomer, the latter canbe recovered by any suitable means and further processed as desired.

In a slurry polymerization process, a suspension of the solid,particulate polymer is formed in the hydrocarbon diluent to whichethylene, α-olefin(s), any optional diene(s) and the components of thecatalyst composition have been added. Slurry polymerization proceedsmuch like solution polymerization.

Preffered polyolefin elastomers that can be obtained by thepolymerization process herein possess a unique combination of highmolecular weight (M_(w)), high Mooney viscosity (ML₁₊₄) lowpolydispersity index (M_(w)/M_(n)), low glass transition temperature(T_(g)) and low hysteresis (tan δ) properties that distinguish them fromknown polyolefin elastomers. The novel polyolefin elastomers of thisinvention prior to curing possess an M_(w) of from about 200,000 toabout 2,000,000, preferably from about 275,000 to about 1,750,000 andmore preferably from about 300,000 to about 1,500,000, an ML₁₊₄ at 125°C. of from about 10 to about 200, preferably from about 15 to about 175and more preferably from about 20 to about 150, an M_(w)/M_(n) of fromabout 1.25 to about 10, preferably from about 1.5 to about 8.5 and morepreferably from about 2.0 to about 7.5, a T_(g)(° C.) of below about−25, preferably below about −30 and more preferably below −35 and a tanδ of from about 0.3 to about 7, preferably from about 0.35 to about 6and more preferably from about 0.4 to about 5.

These advantageous properties can be exploited in a variety of products.Thus, polymer blends can be prepared which contain an elastomer inaccordance with this invention and one or more other hydrocarbonpolymers with which elastomers such as the EPDMs are known to becompatible, e.g., poly(α-olefin) homopolymers and copolymers,polystyrene, ethylene/cycloolefin copolymer, butyl rubber, polyisoprene,polybutadiene, and the like. The elastomer herein can be incorporatedinto any of a wide assortment of rubber articles such as hoses, tubing,power transmission belts including V-belts, conveyor belts, timing beltsand industrial flat belts, air springs, roofing membranes, weatherstripping, bushings, vibration mounts, bridge bearing pads, shoe solesand heels, jacketing for wire or cable, and the like. The elastomer ofthis invention is also useful as a viscosity modifier for lubricatingoils.

To facilitate the manufacture of a polymer blend, the elastomer hereincan be provided as an oil-extended polymer prior to mixing with theother hydrocarbon polymer. The elastomer can be oil-extended by the wellknown procedure of adding oil to the polymer after it is recovered fromthe polymerization reactor. The oil can be selected from the naphthenicor paraffinic oils, typically in amounts of from about 5 to about 150parts by weight of oil per 100 parts by weight of elastomer.Alternatively, part or all of the oil can be added to the elastomer andother hydrocarbon polymer during the blending operation.

The elastomer of this invention can be formulated in a known manner withany of the many usual compounding ingredients, for example, avulcanizing or curative package containing one or more vulcanizingagents, accelerators, activators, retarders, and the like. Other commonformulation ingredients include antiozonants, antioxidants, plasticizingoils and softeners, fillers, reinforcing pigments and carbon blacks.

EXAMPLES

The examples that follow include those that are illustrative of theinvention (Examples 1-27) and those that. are illustrative of knownpolymerization processes, catalysts and elastomers (Comparative Examples1-48). The procatalysts, MAO cocatalyst, cation-generating cocatalystcomponents, solvents and monomers employed in these-examples are asfollows:

1. bis(cyclopentadienyl)zirconium dichloride [Cp₂ZrCl₂]

2. diphenylmethylene(cyclopentadienyl)(fluorenyl)zirconium dichloride[Ph₂C(Cp-9-Flu)ZrCl₂]

3. diphenylsilyl(cyclopentadienyl)(fluorenyl)zirconium dichloride[Ph₂Si(Cp-9-Flu)ZrCl₂]

4. diphenylmethylene(cyclopentadienyl)(indenyl)zirconium dichloride[Ph₂C(Cp-9′-Ind)ZrCl₂]

5. diphenylsilyl(cyclopentadienyl)(indenyl)zirconium dichloride[Ph₂Si(Cp-9′-Ind)ZrCl₂]

6. dimethylmethylene(cyclopentadienyl)(fluorenyl)zirconium dichloride[Me₂C(Cp-9-Flu)ZrCl₂]

7. racemic-dimethylsilylbis(2-methylindenyl)zirconium dichloride[rac-Me₂Si(2-Me-Ind)₂ZrCl₂]

8. dimethylsilylbis(cyclopentadienyl)zirconium dichloride[Me₂Si(Cp)₂ZrCl₂]

9. dimethylsilylbis(fluorenyl)zirconium dichloride [Me₂Si(Flu) ₂ZrCl₂]

10. racemic-ethylenebis(indenyl)zirconium dichloride[rac-Et(Ind)₂ZrCl₂]

11. racemic-dimethylsilylbis(indenyl)zirconium dichloride[rac-Me₂Si(Ind) ₂ZrCl₂]

12. racemic-ethylenebis(indenyl)hafnium dichloride [rac-Et(Ind)₂HfCl₂]

13. racemic-dimethylsilylbis(indenyl)hafnium dichloride[rac-Me₂Si(Ind)₂]

14. dimethylsilyl(tetramethylcyclopentadienyl)(t-butylamido)titaniumdichloride [Me₂Si(Cp*)(NBu^(t))TiCl₂]

15. tris(pentafluorophenyl)borane [B(C₆F₅)₃]

16. trityl tetrakis(pentafluorophenyl)borate [Ph₃CB(C₆F₅)₄]

17. dimethylanilinium tetrakis(pentafluorophenyl)borate[HNMe₂PhB(C₆F₅)₄]

18. lithium tetrakis(pentafluorophenyl)borate[LiB(C₆F₅)₄]

19. methyl aluminoxane [MAO]

20. triisobutylaluminum [Al(Bu^(i))₃], 25 weight % A1 in hexanes, 0.86MA1

Hexane solvent was purified over 3 Å molecular sieves. Toluene solventwas distilled from molten sodium and degassed with dry, deoxygenatedargon. Ethylene and propylene, both high purity grade monomers, werepurified by passage over molecular sieves and a deoxygenation catalyst.The diene monomers 5-ethylidene-2-norbornene [ENB], dicyclopentadiene[DCPD], 5-vinyl-2-norbornene [VNB] and 1,7-octadiene [OD] weredeinhibited over activated alumina and stored over 4 Å molecular sieves.

The following procedures were used to determine the properties of theelastomers.

Weight Average Molecular Weight (M_(w)), Number Average Molecular Weight(M_(n)) and (M_(w)/M_(n))

The molecular weights of the elastomers, M_(w) and M_(n), were measuredin orthodichlorobenzene at 130° C. on a Waters GPC 150C gel permeationchromatograph equipped with a Waters RA401 refractive index detector andWaters Styragel HT columns (10E5 Å, 10E4 Å, 10E3 Å, and 10E6 Å).Molecular weights were calculated from elution times calibrated againstpolystyrene standards from American Polymer Standards Corp. (narrowmolecular weight distribution, M_(n) from 9300 to 2.1×10⁶).

Mooney Viscosity (ML₁₊₄ at 125° C.)

The Mooney viscosity of the elastomers, ML₁₊₄ at 125° C., was measuredon a Monsanto Mooney Viscometer model MV 2000 according to ASTM standardD1646.

Glass Transition Temperature (T_(g))

The glass transition temperatures of the elastomers (T_(g)) weremeasured by differential scanning calorimetry upon 20-25 mg of polymermolded at 150° C. for 15 minutes followed by annealing at roomtemperature for 24 h. T_(g) is reported as the midpoint of the glasstransition on the heating curve of the sample, recorded on a PerkinElmer DSC 7 differential scanning calorimeter (from −100° C. to 180° C.at a heating rate of 20° C./minute).

Hysteresis (Tan δ)

The hysteresis of the elastomers (tan δ; ASTM standard D945) wasdetermined using a Monsanto Rubber Process Analyzer model RPA 2000 andis reported as the average of ten measurements made at 150° C. at afrequency of 0.25 rad/s and at a strain of 1° arc (14%).

Ethylene:Propylene Ratio and Diene Content

The ethylene:propylene ratio and the diene content of the elastomerswere determined by infrared spectroscopy of thin polymer films on aPerkin-Elmer infrared spectrophotometer model Paragon 1000 PC, accordingto ASTM standard D3900.

General Solution Polymerization Procedure A (Emploving an MAOCocatalyst)

The metallocene procatalyst was tared into a hypovial and combined withvigorous mixing under argon with the appropriate aliquot of MAOsolution. The resulting catalyst solution was aged for 30 minutes priorto use. In one polymerization run, 0.056 grams (100 micromoles) ofdiphenylmethylene(cyclopentadienyl)(fluorenyl)zirconium dichloride[Ph₂C(Cp-9-Flu)ZrCl₂] was reacted with 40.0 ml of MAO solution. Thisyielded a catalyst solution with Zr=2.0 mM and an Al/Zr ratio of 1250.

Next, a 2-liter glass reactor was charged with 1500 ml of hexane, 1.2 mlAl(Bu^(i))₃, equivalent to 1.0 mmol A1, the appropriate aliquots ofdiene, and 50 psi each of ethylene and propylene (mass flow ratiodetermined on rotameters) and allowed to thermally equilibrate.

The catalyst solution was then injected into the reactor. Ethylene andpropylene were supplied on demand to maintain reactor pressure at 50psi. The polymerization was terminated with 100 ml of acidified methanol(one volume % concentrated HCl) and the resulting polymer was coagulatedand thereafter mill-dried.

General Solution Polymerization Procedure B (Employing ACation-generating Cocatalyst)

A 2-liter glass reactor was charged with 1500 ml of hexane, 1.2 ml ofAl(Bu^(i))₃ (1.0 mmol A1), the appropriate aliquots of diene and 50 psieach of ethylene and propylene (mass flow ratio determined onrotameters) and allowed to thermally equilibrate. The catalyst, 1.0 mlof a 10 mM solution of Ph₂C(Cp-9-Flu)ZrCl₂ (0.056 g, 100 micromoles in10 ml toluene), was injected into the reactor and allowed to react withthe Al(Bu^(i))₃ for 2 minutes.

The remaining components of the cocatalyst, e.g, 1.0 ml of a 10 mMsolution of B(C₆F₅)₃ (0.102 g, 100 micromol) and LiB(C₆F₅)₄ (0.152 g,100 micromol) in 10 ml of toluene, were injected into the reactor.Ethylene and propylene were supplied on demand to maintain the reactorpressure at 50 psi. Polymerization was terminated with 100 ml ofacidified methanol (1 vol % concentrated HCl) and the resulting polymerwas coagulated and thereafter mill-dried.

The polymer products were analyzed by IR spectroscopy to determine theE:P ratio and diene content. In addition, for most samples, molecularweight (M_(w)) thermal transitions (DSC), tan δ, and Mooney viscosity at125° C. were determined.

The specific polymerization conditions and physical properties of theresulting polymers for each of the examples are summarized in Tables1-6, infra.

Comparative examples 1-19

Employing solution polymerization procedure A described above, severalMAO-activated bridged metallocene catalysts whose bridging groups lackbulky groups were utilized for the attempted preparation of EP andEPDM-type elastomers. The conditions of each polymerization and theproperties of the resulting polymers are summarized below in Table 1.

TABLE 1 A. POLYMERIZATION CONDITIONS AND RESULTS mmol mmol COMP. μmol TFEED DIENE A1 A1 MAO/ TIME YIELD ACTIVITY EX. PROCATALYST M M (° C.) E:PTYPE mL (Bu^(i))₃* MAO M (min) (g) kg/gZr/h  1 rac-Et(Ind)₂ZrCl₂ 2.5 402:1 — — 1.0 2.8 1000 10 79 2009  2 rac-Et(Ind)₂ZrCl₂ 10.0 40 2:1 ENB10.0 1.0 11.2 1000 10 204 1292  3 rac-Et(Ind)₂ZrCl₂ 10.0 40 2:1 DCPD10.0 1.0 11.2 1000 10 110 695  4 rac-Et(Ind)₂HfCl₂ 25.0 40 1:1 — — 1.042.0 1500 30 68 31  5 rac-Et(Ind)₂HfCl₂ 50.0 40 1:1 ENB 5.0 1.0 28.0 50030 100 22  6 rac-Et(Ind)₂HfCl₂ 50.0 40 1:1 DCPD 5.0 1.0 28.0 500 30 8720  7 rac-Me₂Si(Ind)₂ZrCl₂ 2.5 40 2:1 — — 1.0 2.2 872 10 83 2171  8rac-Me₂Si(Ind)₂ZrCl₂ 10.0 40 2:1 ENB 10.0 1.0 8.7 872 10 147 966  9rac-Me₂Si(Ind)₂ZrCl₂ 10.0 40 2:1 DCPD 10.0 1.0 8.7 872 10 43 281 10rac-Me₂Si(Ind)₂HfCl₂ 50.0 40 2:1 — — 1.0 43.6 872 30 67 15 11rac-Me₂Si(Ind)₂HfCl₂ 100.0 40 2:1 ENB 10.0 1.0 87.2 872 30 36 4 12rac-Me₂Si(Ind)₂HfCl₂ 100.0 40 2:1 DCPD 10.0 1.0 87.2 872 30 32 4 13rac-Me₂Si(2-MeInd)₂ZrCl₂ 2.0 40 2:1 — — 1.0 3.1 1560 10 53 1718 14rac-Me₂Si(2-MeInd)₂ZrCl₂ 16.0 40 2:1 ENB 5.0 1.0 12.5 1560 15 32 88 15rac-Me₂Si(2-MeInd)₂ZrCl₂ 16.0 40 2:1 DCPD 5.0 1.0 12.5 1560 15 10 28 16Me₂Si(Flu)₂ZrCl₂ 2.6 40 2:1 — — 1.0 2.8 1080 10 147 3714 17Me₂Si(Flu)₂ZrCl₂ 10.4 40 2:1 ENB 5.0 1.0 11.2 1080 10 77 461 18Me₂Si(Flu)₂ZrCl₂ 10.4 40 2:1 DCPD 5.0 1.0 11.2 1080 10 77 486 19Me₂C(Cp-9-Flu)ZrCl₂ 20.0 40 1:1 — — 1.0 20.6 1030 30 91 99 B. POLYMERPROPERTIES COMP. ML₁₊₄ POLYMER DIENE EX. M_(w) × 10³ M_(w)/M_(n) (125°C.) E:P (wt %) Tg (° C.) tan δ COMMENT  1 161 1.85 low 82:18 — −39 n.d.Low Mooney  2 142 2.15 low 69:31 6.6 −49 n.d. Low Mooney  3 159 1.92 low80:20 9.9 −31 n.d. Low Mooney  4 616 2.06 90 59:41 — −57 n.d. Lowactivity  5 514 2.19 70 59:41 3.7 −52 n.d. Low activity  6 582 2.37 9159:41 4.5 −51 n.d. Low activity  7 184 2.03 low 76:24 — −38 n.d. LowMooney  8 164 2.07 low 70:30 4.9 −45 n.d. Low Mooney  9 197 1.83 low80:20 11.0 −28 n.d. Low Mooney 10 443 2.31 n.d. 65:35 — −55 n.d. Lowactivity 11 162 2.02 low 68:32 12.1 −42 n.d. Low activity 12 213 1.84low 69:31 13.6 −38 n.d. Low activity 13 336 1.98 35 80:20 — −39 2.7 — 14330 1.86 45 78:22 0.0 −38 2.9 No diene incorporation; diene inhibitionof activity 15 320 1.89 n.d. 79:21 0.0 −38 3.4 No diene incorporation;diene inhibition of activity 16 486 2.05 52 68:32 — −58 n.d. — 17 4771.96 48 83:17 0.0 −61 n.d. No diene incorporation; diene inhibition ofactivity 18 409 1.95 43 79:21 0.0 −58 n.d. No diene incorporation; dieneinhibition of activity 19 44 1.92 low 58:42 — n.d. n.d. Low Mooney, lowactivity *Added to reduce the MAO/Zr AND MAO/Hf ratios.

As these data show, Comparative Examples 1-3 and 7-9 illustrating theuse of zirconium-based metallocene catalysts yielded low Mooneyviscosity polymers and Comparative Examples 4-6 and 10-12 illustratingthe use of hafnium-based metallocene catalysts exhibited unacceptablylow activity. All of the catalysts employed in Comparative Examples 1-13showed relatively poor activity toward propylene. Comparative Examples14, 15, 17 and 18 yielded copolymers only, not terpolymers; there was nodiene incorporation and diene inhibition was observed. ComparativeExample 19 showed low catalyst activity and the resulting elastomerpossessed low Mooney viscosity.

Examples 1-3

Employing solution polymerization procedure A described above,MAO-activated bridged metallocene catalysts whose bridging groupspossess two bulky groups were utilized for the production of elastomers.The conditions of each polymerization and the properties of theresulting elastomers are summarized in Table 2.

TABLE 2 EXAMPLES 1-3 A. POLYMERIZATION CONDITIONS DIENE EX. PROCATALYSTM μmol M T (° C.) FEED E:P TYPE mL mmol Al (Bu^(i))₃* mmol Al (MAO)MAO/M 1 Ph₂C(Cp-9-Flu)ZrCl₂ 10.0 40 2:1 — — 1.0 25.0 2500 2Ph₂C(Cp-9-Flu)ZrCl₂ 10.0 40 2:1 ENB 10.0 1.0 25.0 2500 3Ph₂C(Cp-9-Flu)ZrCl₂ 10.0 40 2:1 DCPD 10.0 1.0 25.0 2500 B.POLYMERIZATION RESULTS AND POLYMER PROPERTIES TIME YIELD ACTIVITY ML₁₊₄POLYMER DIENE EX. (min) (g) kg/gZr/h M_(w) × 10³ M_(w)/M_(n) (125° C.)E.P. (wt %) Tg (° C.) tan δ COMMENT 1 15 99 433 260 1.92 22 71:29 — −43n.d. High MAO/Zr required for good results 2 15 90 394 232 2.00 20 70:307.2 −41 n.d High MAO/Zr required for good results 3 15 92 403 232 2.0221 71:29 6.9 −39 n.d: High MAO/Zr required for good results *Added toreduce the MAO/Zr ratios.

In these examples, the yields were high and good E:P ratio wereconsistently achieved. In Examples 2 and 3, diene was successfullyincorporated into the polymers to provide EPDM elastomers. All of theelastomers exhibited good properties. Examples 1 to 3 also demonstratethe typically high ratios of MAO to metallocene that are needed for goodresults.

Examples 4-9

The polymerization procedures used in these examples are similar tothose employed in Examples 1-3 and are intended to show the beneficialeffects of employing an additional diene monomer as a branching agentupon certain of the properties of the resulting EPDM-type elastomers,specifically, their Mooney viscosity, M_(w), M_(w)/M_(n) and tan δvalues. The conditions of each polymerization and the properties of theresulting polymers are summarized in Table 3.

TABLE 3 EXAMPLES 4-9 A. POLYMERIZATION CONDITIONS mmol mmol DIENEBRANCHING AGENT Al Al EX. PROCATALYST M μmol M T (° C.) FEED E:P TYPE mLTYPE mL (Bu^(i))₃* (MAO) MAO/M 4 Ph₂C(Cp-9-Flu)ZrCl₂ 10.0 70 2:1 ENB 5.0— — 1.0 25.0 2500 5 Ph₂C(Cp-9-Flu)ZrCl₂ 10.0 70 2:1 ENB 4.88 VNB 0.121.0 25.0 2500 6 Ph₂C(Cp-9-Flu)ZrCl₂ 10.0 70 2:1 ENB 4.75 VNB 0.25 1.025.0 2500 7 Ph₂C(Cp-9-Flu)ZrCl₂ 10.0 70 2:1 ENB 4.5 VNB 0.5 1.0 25.02500 8 Ph₂C(Cp-9-Flu)ZrCl₂ 10.0 40 2:1 ENB 9.5 OD 0.5 1.0 12.5 1250 9Ph₂C(Cp-9-Flu)ZrCl₂ 10.0 70 2:1 ENB 9.5 OD 0.5 1.0 12.5 1250 B.POLYMERIEATION RESULTS AND POLYMER PROPERTIES TIME YIELD ACTIVITY ML₁₊₄POLYMER DIENE EX. (min) (g) kg/gZr/h M_(w) × 10³ M_(w)/M_(n) (125° C.)E.P. (wt %) Tg (° C.) tan δ COMMENT 4 15 90 394 214 1.93 16 77.23 5.6−33 4.5 High MAO/Zr required for good results 5 15 92 404 227 2.08 2176:24 5.5 −37 1.8 High MAO/Zr required for good results 6 15 89 390 2722.42 31 77:23 5.6 −35 0.9 High MAO/Zr required for good results 7 15 91399 354 2.75 44 77:23 5.1 −34 0.6 High MAO/Zr required for good results8 15 36 156 378 2.18 91 75:25 13.0 n.d. n.d High MAO/Zr required forgood results 9 15 34 148 291 2.26 65 77:23 16.4 n.d. n.d. High MAO/Zrrequired for good results

Examples 4 to 7 employing a MAO/metallocene ratio twice as high as thatof Example 8 and 9 resulted in much greater yields and much higheractivities that the latter further demonstrating the need to utilizevery high MAO/metallocene ratios in order to achieve optimum processresults. Examples 5 to 9 show that incorporation of a branching dieneresulted in improvements in the Mooney viscosity, M_(w), M_(w)/M_(n) andtan δ values (where determined) of each elastomer relative to theelastomer of Example 4 which contained no branching diene.

Comparative examples 20-23 Examples 10-19

Employing solution polymerization procedure B described above,metallocene catalysts whose bridging groups possess two bulky groups andwhich were activated by cation-generating cocatalyst both within(Examples 10-19) and outside (Comparative Examples 20-23) the scope ofthe invention were used for the preparation of EPDM elastomers. Theconditions of each polymerization and the properties of the resultingpolymers are summarized in Table 4.

TABLE 4 COMPARATIVE EXAMPLES 20-23; EXAMPLES 10-19 A. POLYMERIZATIONCONDITIONS COMP. BRANCHING CATION-GENERATING COCATALYST EX./ μmol T FEEDDIENE AGENT mmol BORON EX. PROCATALYST M M (° C.) E:P TYPE mL TYPE mL Al(Bu^(i))₃ CMPD (S)* μmol B B/M 20 Ph₂C(Cp-9-Flu)ZrCl₂ 10.0 70 2:1 ENB4.5 VNB 0.5 1.0 B 20 2 21 Ph₂C(Cp-9-Flu)ZrCl₂ 10.0 70 2:1 ENB 4.5 VNB0.5 1.0 Ph₃C 10 1 22 Ph₂C(Cp-9-Flu)ZrCl₂ 10.0 70 2:1 ENB 4.5 VNB 0.5 1.0HNMe₂Ph 20 2 23 Ph₂C(Cp-9-Flu)ZrCl₂ 10.0 70 2:1 ENB 4.5 VNB 0.5 1.0 LiB20 2 10 Ph₂C(Cp-9-Flu)ZrCl₂ 10.0 70 2:1 ENB 4.5 VNB 0.5 1.0 LiB + B 20 211 Ph₂C(Cp-9-Flu)ZrCl₂ 10.0 40 1:1 ENB 9.75 VNB 0.25 1.0 LiB + B 20 2 12Ph₂C(Cp-9-Flu)ZrCl₂ 10.0 40 1.25:1 ENB 9.75 VNB 0.25 1.0 LiB + B 20 2 13Ph₂C(Cp-9-Flu)ZrCl₂ 10.0 40 1.5:1 ENB 9.75 VNB 0.25 1.0 LiB + B 20 2 14Ph₂C(Cp-9-Flu)ZrCl₂ 10.0 40 1.5:1 ZNB 9.65 VNB 0.35 1.0 LiB + B 20 2 15Ph₂C(Cp-9-Flu)ZrCl₂ 10.0 40 2:1 ENB 9.75 OD 0.25 1.0 LiB + B 20 2 16Ph₂Si(Cp-9-Flu)ZrCl₂ 10.0 40 1:1 ENB 4.82 VNB 0.18 1.0 LiB + B 20 2 17Ph₂Si(Cp-9-Flu)ZrCl₂ 10.0 40 1.25:1 ENB 4.82 VNB 0.18 1.0 LiB + B 20 218 Ph₂Si(Cp-9-Flu)ZrCl₂ 10.0 40 1.5:1 ENB 4.82 VNB 0.18 1.0 LiB + B 20 219 Ph₂Si(Cp-9-Flu)ZrCl₂ 10.0 40 2:1 ENB 4.82 VNB 0.18 1.0 LiB + B 20 2B. POLYMERIZATION RESULTS AND POLYMER PROPERTIES COMP. EX./ TIME YIELDACTIVITY ML₁₊₄ POLYMER DIENE EX. (min) (g) kg/gZr/h M_(w) × 10³M_(w)/M_(n) (125° C.) E.P. (wt %) Tg (° C.) tan δ COMMENT 20 10 12  80n.d. n.d. n.d. n.d. n.d. n.d. n.d. Short-lived 21 10 55 362 415 2.96 5374.26 4.5 −37 0.53 Short-lived with very high initial activity 22 10111  730 620 3.38 127  n.d. n.d. −34 n.d. Short-lived with very highinitial activity; gel formed 23 10  0 — — — — — — — — No activity 10 1096 635 421 2.58 62 74.26 4.3 −39 0.61 Superior to those produced withMAO catalyst 11 10 99 655 233 2.47 36 52:48 7.2 −50 1.5 Superior tothose produced with MAO catalyst 12 10 111  734 287 2.60 51 61:39 6.8−49 0.89 Superior to those produced with MAO catalyst 13 10 106  705 3342.74 62 66:34 7.4 −47 0.72 Superior to those produced with MAO catalyst14 10 115  761 430 3.53 78 59:41 5.6 −50 n.d Superior to those producedwith MAO catalyst 15 10 101  670 613 3.63 94 70:30 7.4 −44 0.42 Superiorto those produced with MAO catalyst 16 10 75 495 699 2.20 — 66:34 3.8−43 1.03 Mooney too high to be measured 17 10 68 453 820 2.37 — 70:304.3 n.d. n.d. Mooney too high to be measured 18 10 66 435 935 2.36 —74:26 4.4 n.d. n.d. Mooney too high to be measured 19 10 74 488 928 2.39— 77:23 4.3 n.d. n.d. Mooney too high to be measured *B = B(C₆F₅)₃; Ph₃C= Ph₃CB(C₆F₅)₄; HNMe₂Ph = HNMe₂PhB(C₆F₅)₄; LiB = LiB(C₆F₅)₄.

As these data show, the catalysts utilized in Comparative Examples 20-23were short lived and resulted in little or no activity after an initialburst of high activity (the catalyst of Comparative Example 23 showed noactivity at all). In contrast to these results, Examples 10-19illustrating the use of a cation-generating cocatalyst in accordancewith this invention showed consistently good activity for the entirepolymerization term, a result demonstrating its much greater stabilitythan the cation-generating cocatalysts of the comparative examples. Thisresult is all the more surprising considering that the boron-containingcompounds of the cation-generating cocatalyst of this invention whenemployed individually as in Comparative Examples 20 and 23 giveunacceptable results.

Comparative examples 24-43; Examples 20-24

Employing essentially the same procedures as in Comparative Examples20-23/Examples 10-19, polymerizations were carried out with variousmetallocene catalysts that had been activated by cation-generatingcocatalysts both within (Examples 20-24) and outside (ComparativeExamples 24-43) the scope of the invention. The conditions of eachpolymerization and its results are summarized in Table 5.

TABLE 5 COMPARATIVE EXAMPLES 24-43; EXAMPLES 20-24 A. POLYMERIZATIONCONDITIONS COMP. CATION-GENERATING COCATALYST EX./ PRO- μmol T FEED mLmmol Al BORON μmol TIME YIELD ACTIVITY EX. CATALYST M M (° C.) E:P ENB(Bu^(i))₃ CMPD (S)* B B/M (min) (g) kg/gZr/H COMMENT 24 Cp₂ZrCl₂ 2.5 401:1 5.0 1.0 B 5 2 10 7 175 Short-lived 25 Cp₂ZrCl₂ 2.5 40 1:1 5.0 1.0LiB 5 2 10 0 — No activity 26 Cp₂ZrCl₂ 2.5 40 1:1 5.0 1.0 Ph₃C 5 2 10 53894 Short-lived with very high initial activity 27 Cp₂ZrCl₂ 2.5 40 1:15.0 1.0 HNMe₂Ph 5 2 10 38 649 Short-lived, high initial activity 20Cp₂ZrCl₂ 2.5 40 1:1 5.0 1.0 LiB + B 5 2 10 37 631 No decrease inactivity with time 28 Me₂Si(Cp)₂ 10.0 40 1:1 5.0 1.0 B 20 2 10 9 58Short-lived ZrCl₂ 29 Me₂Si(Cp)₂ 10.0 40 1:1 5.0 1.0 LiB 20 2 10 5 36Very low ZrCl₂ activity 30 Me₂Si(Cp)₂ 10.0 40 1:1 5.0 1.0 Ph₃C 20 2 1030 212 Short-lived ZrCl₂ with very high activity 31 Me₂Si(Cp)₂ 10.0 401:1 5.0 1.0 HNMe₂Ph 20 2 10 20 139 Short-lived, ZrCl₂ high initialactivity, gel 21 Me₂Si(Cp)₂ 10.0 40 1:1 5.0 1.0 LiB + B 20 2 10 24 175No decrease in ZrCl₂ activity with time 32 rac-Et(Ind)₂ 2.5 40 1:1 5.01.0 B 5 2 10 10 292 Short-lived ZrCl₂ 33 rac-Et(Ind)₂ 2.5 40 1:1 5.0 1.0LiB 5 2 10 0 — No activity ZrCl₂ 34 rac-Et(Ind)₂ 2.5 40 1:1 5.0 1.0 Ph₃C5 2 10 228 5642 Short-lived ZrCl₂ with very high initial activity 35rac-Et(Ind)₂ 2.5 40 1:1 5.0 1.0 HNMe₂Ph 5 2 10 169 4239 Short-lived,ZrCl₂ high initial activity, gel 22 rac-Et(Ind)₂ 2.5 40 1:1 5.0 1.0LiB + B 5 2 10 146 3712 No decrease in ZrCl₂ activity with time 36Me₂C(Cp-9- 10.0 40 1:1 5.0 1.0 B 20 2 10 9 65 Short-lived Flu)ZrCl₂ 37Me₂C(Cp-9- 10.0 40 1:1 5.0 1.0 LiB 20 2 10 0 — No activity Flu)ZrCl₂ 38Me₂C(Cp-9- 10.0 40 1:1 5.0 1.0 Ph₃C 20 2 10 69 467 Short-lived Flu)ZrCl₂with very high initial activity 39 Me₂C(Cp-9- 10.0 40 1:1 5.0 1.0HNMe₂Ph 20 2 10 46 321 Short-lived Flu)ZrCl₂ high initial activity, gel23 Me₂C(Cp-9- 10.0 40 1:1 5.0 1.0 LiB + B 20 2 10 55 380 Slight decreaseFlu)ZrCl₂ in activity with time 40 Me₂Si(Cp*) 10.0 40 1:1 5.0 1.0 B 20 210 9 97 Short-lived (NBu^(t))TiCl₂ 41 Me₂Si(Cp*) 10.0 40 1:1 5.0 1.0 LiB20 2 10 0 — No activity (NBu^(t))TiCl₂ 42 Me₂Si(Cp*) 10.0 40 1:1 5.0 1.0Ph₃C 20 2 10 107 1349 Short-lived (NBu^(t))TiCl₂ with very high initialactivity 43 Me₂Si(Cp*) 10.0 40 1:1 5.0 1.0 HNMe₂Ph 20 2 10 90 1154Short-lived, (NBu^(t))TiCl₂ high initial activity, gel 24 Me₂Si(Cp*)10.0 40 1:1 5.0 1.0 LiB + B 20 2 10 94 1196 No decrease in(NBu^(t))TiCl₂ activity with time *B = B(C₆F₅)₃; Ph₂C = Ph₃CB(C₆F₅)₄;HNMe₂Ph = HNMe₂Ph B(C₆F₅)₄; LiB = LiB(C₆F₅)₄.

While the Al(Bu^(i))₃+Ph₃C cocatalyst yields an activated metallocenecatalyst with very high initial activity (Comparative Examples 26, 30,34, 38 and 42), the activity is short-lived compared to the far morestable catalysts that are obtained by activating the metalloceneprocatalysts with a cation-generating cocatalyst of this invention(Examples 20-24). This difference in results is graphically shown inaccompanying FIG. 1 which presents a comparison in monomer consumptionover time between-procatalyst activated with Al(Bu^(i))₃+Ph₃C(Comparative Example 30) and procatalyst activated withAl(Bu^(i))₃+LiB+B (Example 21). The catalyst obtained withAl(Bu^(i))₃+Ph₃C cocatalyst lost all activity within a matter of minuteswhile the catalyst obtained with the Al(Bu^(i))₃+LiB+B cocatalyst ofthis invention continued to provide good activity for the entire 10minutes of polymerization indicated and well beyond.

Largely the same sort of instability observed for metallocenes obtainedwith the Al(Bu^(i))₃+PH₃C cocatalyst was also evident in themetallocenes activated with the Al(Bu^(i))₃+HNMe₃Ph cocatalyst ofComparative Examples 27, 31, 35 and 39), the latter exhibiting thefurther disadvantage of causing gelation of the polymer.

Comparative examples 44-48; Examples 25-27

Comparative Examples 44-48 utilized solution polymerization procedure Aand are illustrative of the use of a known type of MAO-activatedcatalyst. Examples 25-27 utilized solution polymerization procedure Band illustrate the use of a catalyst obtained by activating the sameprocatalyst employed in the comparative examples with acation-generating cocatalyst in accordance with the invention. Theconditions of the polymerizations, their results and the properties ofthe product polymers are summarized in Table 6.

TABLE 6 COMPARATIVE EXAMPLES 44-48; EXAMPLES 25-27 A. POLYMERIZATIONCONDITIONS MAO CATION- COMP. BRANCHING COCATALYST GENERATING COCATALYSTEX./ PRO- μmol T FEED DIENE DIENE mmol Al MAO/ mmol BORON EX. CATALYST MM (° C.) E:P TYPE mL TYPE mL (MAO) M Al (Bu^(i))₃ CMPD (S)* μmol B B/M44 Me₂Si(Cp*) 12.5 40 2:1 ENB 5.0 — — 4.12 3300 1.0 — — — (NBu^(t))TiCl₂45 Me₂Si(Cp*) 12.5 40 2:1 ENB 4.88 VNB 0.12 4.12 3300 1.0 — — —(NBu^(t))TiCl₂ 46 Me₂Si(Cp*) 12.5 70 2:1 ENB 5.0 — — 4.12 3300 1.0 — — —(NBu^(t))TiCl₂ 47 Me₂Si(Cp*) 12.5 70 2:1 ENB 4.88 VNB 0.12 4.12 3300 1.0— — — (NBu^(t))TiCl₂ 48 Me₂Si(Cp*) 12.5 70 2:1 ENB 4.75 VNB 0.25 4.123300 1.0 — — — (NBu^(t))TiCl₂ 25 Me₂Si(Cp*) 12.5 70 2:1 ENB 5.0 — — — —1.0 LiB + B 25 2 (NBu^(t))TiCl₂ 26 Me₂Si(Cp*) 12.5 70 2:1 ENB 4.75 OD0.25 — — 1.0 LiB + B 25 2 (NBu^(t))TiCl₂ 27 Me₂Si(Cp*) 12.5 70 2:1 ENB4.5 OD 0.5 — — 1.0 LiB + B 25 2 (NBu^(t))TiCl₂ B. POLYMERIZATION RESULTSAND POLYMER PROPERTIES COMP. EX./ TIME YIELD ACTIVITY ML₁₊₄ POLYMERDIENE Tg EX. (min) (g) kg/gZr/h M_(w) × 10³ M_(w)/M_(n) (125° C.) E:P(wt %) (° C.) tan δ COMMENT 44 30 48 326 338 2.00 42 59:41 5.8 −45 3.28High MAO/Zr 45 30 50 337 438 2.26 72 62:38 5.8 −43 1.16 High MAO/Zr 4615 72 484 323 2.02 37 70:30 4.1 −37 2.67 High MAO/Zr, high T₂ 47 15 83555 368 2.13 44 69:31 3.7 −38 1.75 High MAO/Zr, high T₂ 48 15 74 498 3842.21 53 71:29 3.8 −36 1.27 High MAO/Zr, high T₂ 25 15 93 618 509 2.31 8968:32 4.2 −40 1.72 Higher activity, M_(w) than with MAO 26 15 91 601 5402.57 94 67:33 3.8 −40 0.54 OD very effective 27 15 92 622 598 2.77 10468:32 3.9 −42 0.49 Little additive benefit for additional OD *B =B(C₆F₅)₃; LiB = LiB(C₆F₅)₄.

When using MAO as the procatalyst (Comparative Examples 44-48), anextraordinarily high MAO/procatalyst ratio is required in order achieveacceptable catalytic activity. Especially at a higher temperature (70°C.), the reactivity of propylene is unfavorable and the Tg of theproduct polymer is unacceptably high. In contrast to these results, theuse of the cation-generating cocatalyst of this invention to activatethe procatalyst (Examples 25-27) provided higher yields and greateractivities and produced polymers with better M_(w), ML₁₊₄ and T_(g).

In an alternate embodiment of this invention it is contemplated thatthrough the use, during polymerization, of known chain transfer agents,such as hydrogen, the molecular weights of the elastomers describedherein can be intentionally and substantially reduced resulting in lowmolecular weight, even liquid polymers which may be desireable inparticular end use applications.

What is claimed is:
 1. A process for the liquid phase polymerization ofethylene, at least one other α-olefin and, optionally, at least onediene monomer to provide an elastomer, the process comprisingpolymerizing the monomer under liquid phase elastomer-formingpolymerization conditions in the presence of a catalytically effectiveamount of catalyst comprising the product obtained by combining ametallocene procatalyst with a cocatalyst, the metallocene procatalystbeing at least one compound of general formulae (I) and/or (II): (Cp¹R¹_(m))R³ _(n)(Cp²R² _(p))MX_(q)  (I) (Cp¹R¹ _(m))R³ _(n)Y_(r)MX_(s)  (II)wherein Cp¹ of ligand (Cp¹R¹ _(m)) and Cp² of ligand (Cp²R² _(p)) arethe same or different cyclopentadienyl rings, R¹ and R² each is,independently, halogen or a hydrocarbyl, halocarblyl,hydrocarbyl-substituted organometalloid or halocarbyl-substitutedorganometalloid group containing up to about 20 carbon atoms, m is 0 to5, p is 0 to 5 and two R¹ and/or R² substituents on adjacent carbonatoms of the cyclopentadienyl ring associated therewith can be joinedtogether to form a ring fused to the cyclopentadienyl ring, the fusedring containing from 4 to about 20 carbon atoms, R³ is a bridging groupbridging Cp¹ and Cp² or bridging Cp¹ and Y_(r), n is 0 or 1, Y is aheteroatom-containing ligand in which the heteroatom is coordinated toM, M is a transition metal having a valence of from 3 to 6, each X is anon-cyclopentadienyl ligand and is, independently, halogen or ahydrocarbyl, oxyhydrocarbyl, halocarbyl, hydrocarbyl-substitutedorganometalloid, oxyhydrocarbyl-substituted organometalloid orhalocarbyl-substituted organometalloid group containing up to about 20carbon atoms, q is equal to the valence of M minus 2, r has the value ofn and s is equal to the valence of M minus 1 when r is 0 and is equal tothe valence of M minus 2 when r is 1, the cocatalyst is entirely analuminoxane or combination of aluminoxane and added trialkylaluminum ora different cation-generating cocatalyst comprising: a metal- and/ormetalloid-containing first component capable of exchanging at least oneX ligand in the metallocene procatalyst up to the total number thereofwith, independently, a hydrogen atom, or a carbohydryl group containingup to about 20 carbon atoms or an oxycarbohydryl group containing up to20 carbon atoms; a neutral metal- and/or metalloid-containing secondcomponent having at least one aryl group possessing at least oneelectron-withdrawing substituent; and, an anionic metal-containing thirdcomponent having at least one aryl group possessing at least oneelectron-withdrawing constituent alone or in combination with an anionicmetalloid-containing third components having at least one aryl grouppossessing at least electron-withdrawing constituent, provided, thatwhen the metallocene procatalyst is one of formula (I) and thecocatalyst is entirely an aluminoxane, or combination of aluminoxane andadded trialkylaluminum, ligand (Cp¹R¹ _(m)) is different from ligand(Cp²R² _(p)), bridging group R³ contains at least two bulky groups and nis 1 and when the procatalyst is entirely one of formula (II), thecocatalyst comprises said different cation-generating cocatalyst.
 2. Theprocess of claim 1 wherein in metallocene procatalyst (I), bridginggroup R³ possesses the structure

in which groups R⁴ and R⁵ each, independently, is, or contains, a cyclicgroup of from 6 to about 20 carbon atoms, from 0 to 3 heteroatoms andhydrogen as the remaining atoms.
 3. The process of claim 2 wherein inmetallocene procatalyst (I), the cyclic group is a cycloalkyl,heterocycloalkyl, cycloalkenyl, heterocycloalkenyl, aryl, heteroaryl,alkaryl, allylheteroaryl, aralkyl or heteroaralkyl group.
 4. The processof claim 3 wherein in metallocene procatalyst (I), ligand (Cp¹R_(m) ¹)is unsubstituted cyclopentadienyl, ligand (Cp²R_(p) ²) is substituted orunsubstituted indenyl or fluorenyl, M¹ is zirconium, R⁴ and R⁵ each isphenyl and each ligand X is chlorine.
 5. The process of claim 1 whereinin metallocene procatalyst (II), n and r are both 1, the valence of M is4, ligand X is halogen and s is
 2. 6. The process of claim 1 wherein inthe different cation-generating cocatalyst, the first component is analuminum compound, the second component is a borane compound and thethird component is a metal borate compound.
 7. The process of claim 6wherein the aluminum compound is a trialkylaluminum or dialkylaluminumhydride, the borane compound is a tris(haloaryl)borane and the metalborate compound is an alkali metal-, alkaline earth metal-, ortransition metal-tetrakis(haloaryl)borate.
 8. The process of claim 7wherein the aluminum compound is a trialkylaluminum, the borane compoundis a tris(halophenyl)borane and the metal borate compound is an alkalimetal tetrakis(halophenyl)borate.
 9. The process of claim 6 wherein thealuminum compound is at least one of trimethylaluminum,triethylaluminum, tri(n-propyl)aluminum, triisopropylaluminum,tri(n-butyl)aluminum, tri(n-propyl)aluminum, triisobutylaluminum,tri(n-hexyl)aluminum, tri(n-octyl) aluminum, dimethyaluminum hydride,diethylaluminum hydride, diisopropylaluminum hydride,di(n-propyl)aluminum hydride, diisobutylaluminum hydride,di(n-butyl)aluminum hydride, dimethylaluminum ethoxide,di(n-propyl)aluminum ethoxide, diisobutylaluminum ethoxide ordi(n-butyl)aluminum ethoxide, the borane compound is at least one oftris(pentafluorophenyl)borane, tris(methoxyphenyl)borane,tris(trifluoromethylphenyl)borane, tris(3,5-di[trifluoromethyl]phenyl)borane, tris(tetrafluoroxylyl)borane or tris(tetrafluoro-o-tolyl)boraneand the metal borate compound is at least one of lithiumtetrakis(trifluoromethylphenyl)borate, lithiumtetrakis(pentafluorophenyl)borate, lithiumtetrakis(3,5-di[trifluoromethyl]phenyl)borate, sodium tetrakis(pentafluorophenyl)borate, potassium tetrakis(pentafluoro-phenyl)borate,magnesium tetrakis(pentafluorophenyl)borate, titaniumtetrakis(pentafluorophenyl)borate or tin tetrakis(pentafluorophenyl)borate.
 10. The process of claim 1 wherein themetallocene procatalyst is combined with the components of the differentcation-generating cocatalyst in the presence of monomer.
 11. The processof claim 2 wherein the metallocene procatalyst is combined with thecomponents of the different cation-generating cocatalyst in the presenceof monomer.
 12. The process of claim 3 wherein the metalloceneprocatalyst is combined with the components of the differentcation-generating cocatalyst in the presence of monomer.
 13. The processof claim 4 wherein the metallocene procatalyst is combined with thecomponents of the different cation-generating cocatalyst in the presenceof monomer.
 14. The process of claim 5 wherein the metalloceneprocatalyst is combined with the components of the differentcation-generating cocatalyst in the presence of monomer.
 15. The processof claim 6 wherein the metallocene procatalyst is combined with thecomponents of the different cation-generating cocatalyst in the presenceof monomer.
 16. The process of claim 7 wherein the metalloceneprocatalyst is combined with the components of the differentcation-generating cocatalyst in the presence of monomer.
 17. The processof claim 8 wherein the metallocene procatalyst is combined with thecomponents of the different cation-generating cocatalyst in the presenceof monomer.
 18. The process of claim 9 wherein the metalloceneprocatalyst is combined with the components of the differentcation-generating cocatalyst in the presence of monomer.
 19. The processof claim 1 wherein the α-olefin contains from 3 to about 20 carbonatoms.
 20. The process of claim 19 wherein the α-olefin is propylene.21. The process of claim 20 wherein one diene is a nonbranching dieneand another diene is a branching diene.
 22. The process of claim 1wherein polymerization is carried out under solution polymerizationconditions.
 23. The process of claim 1 wherein polymerization is carriedout under slurry polymerization conditions.
 24. The process of claim 5wherein in metallocene procatalyst (II), bridging group R³ possesses thestructure

in which groups R⁴ and R⁵ each, independently, is, alkyl from 1 to about5 carbon atoms or a cyclic group of from about 6 to about 20 carbonatoms.
 25. The process of claim 24 wherein in metallocene catalyst (II),ligand (Cp¹R¹ _(m)) is substituted cyclopentadienyl, M is selected fromthe group consisting of titanium and zirconium, Y is t-butylamide, R⁴and R⁵ each is methyl and each ligand X is chlorine.
 26. A process forthe polymerization of olefin to provide a polyolefin, the processcomprising polymerizing at least one olefin in the presence of acatalytically effective amount of catalyst comprising the productobtained by combining a metallocene procatalyst with a cocatalyst, themetallocene procatalyst being at least one compound of general formulae(I) and/or (II): (Cp¹R¹ _(m))R³ _(n)(Cp²R² _(p))MX_(q)  (I) (Cp¹R¹_(m))R³ _(n)Y_(r)MX_(s)  (II) wherein Cp¹ of ligand (Cp¹R¹ _(m)) and Cp²of ligand (Cp²R² _(p)) are the same or different cyclopentadienyl rings,R¹ and R² each is, independently, halogen or a hydrocarbyl, halocarbyl,hydrocarbyl-substituted organometalloid or halocarbyl-substitutedorganometalloid group containing up to about 20 carbon atoms, m is 0 to5, p is 0 to 5 and two R¹ and/or R² substituents on adjacent carbonatoms of the cyclopentadienyl ring associated therewith can be joinedtogether to form a ring fused to the cyclopentadienyl ring, the fusedring containing from 4 to about 20 carbon atoms, R³ is a bridging groupbridging Cp¹ and Cp² or bridging Cp¹ and Y_(r), n is 0 or 1, Y is aheteroatom-containing ligand in which the heteroatom is coordinated toM, M is a transition metal having a valence of from 3 to 6, each X is anon-cyclopentadienyl ligand and is, independently, halogen or ahydrocarbyl, oxyhydrocarbyl, halocarbyl, hydrocarbyl-substitutedorganometalloid, oxyhydrocarbyl-substituted organometalloid orhalocarbyl-substituted organometalloid group containing up to about 20carbon atoms, q is equal to the valence of iM minus 2, r has the valueof n and s is equal to the valence of M minus 1 when r is 0 and is equalto the valence of M minus 2 when r is 1, the cocatalyst comprising: ametal- and/or metalloid-containing first component capable of exchangingat least one X ligand in the metallocene procatalyst up to the totalnumber thereof with, independently, a hydrogen atom or a carbohydrylgroup containing up to about 20 carbon atoms or oxycarbohydryl groupcontaining up to 20 carbon atoms; a neutral metal- and/ormetalloid-containing second component having at least one aryl grouppossessing at least one electron-withdrawing substituent; and, ananionic metal-containing third component having at least one aryl grouppossessing at least one electron-withdrawing substituent alone or incombination with an anionic metalloid-containing third component havingat least one aryl group possessing at least one electorn-withdrawingsubstituent.
 27. The process of claim 26 wherein in the cocatalyst, thefirst component is an aluminum compound, the second component is aborane compound and the third component is a metal borate compound. 28.The process of claim 27 wherein the aluminum compound is atrialkylaluminum or dialkylaluminum hydride, the borane compound is atris(haloaryl)borane and the metal borate compound is an alkali metal-,alkaline earth metal-, or transition metal-tetrakis(haloaryl)borate. 29.The process of claim 28 wherein the aluminum compound is atrialkylaluminum, the borane compound is a tris(halophenyl)borane andthe metal borate compound is an alkali metal tetrakis(halophenyl)borate.30. The process of claim 27 wherein the aluminum compound is at leastone of trimethylaluminum, triethylaluminum, tri(n-propyl)aluminum,triisopropylaluminum, tri(n-butyl)aluminum, tri(n-propyl)aluminum,triisobutylaluminum, tri(n-hexyl)aluminum, tri(n-octyl)aluminum,dimethyaluminum hydride, diethylaluminum hydride, diisopropylaluminumhydride, di(n-propyl)aluminum hydride, diisobutylaluminum hydride,di(n-butyl)aluminum hydride, dimethylaluminum ethoxide,di(n-propyl)aluminum ethoxide, diisobutylaluminum ethoxide ordi(n-butyl)aluminum ethoxide, the borane compound is at least one oftris(pentafluorophenyl)borane, tris(methoxyphenyl)borane,tris(trifluoromethylphenyl)borane,tris(3,5-di[trifluoromethyl]phenyl)borane, tris(tetrafluoroxylyl)boraneor tris(tetrafluoro-o-tolyl)borane and the metal borate compound is atleast one of lithium tetrakis(pentafluorophenyl)borate, lithiumtetrakis(trifluoromethylphenyl)borate, lithium tetrakis(3,5-di[trifluoromethyl]phenyl)borate, sodium tetrakis(pentafluorophenyl)borate, potassium tetrakis(pentafluorophenyl)borate,magnesium tetrakis(pentafluorophenyl)borate, titaniumtetrakis(pentafluorophenyl)borate or tin tetrakis(pentafluorophenyl)borate.
 31. The process of claim 26 wherein themetallocene procatalyst is combined with the components of thecocatalyst in the presence of olefin.
 32. The process of claim 26wherein the olefin is ethylene, propylene or a mixture of ethylene andpropylene.
 33. The process of claim 26 wherein in metalloceneprocatalyst (I), bridging group R³ possesses the structure

in which groups R⁴ and R⁵ each, independently, is, or contains, a cyclicgroup of from 6 to about 20 carbon atoms, from 0 to 3 heteroatoms andhydrogen as the remaining atoms.
 34. The process of claim 33 wherein inmetallocene procatalyst (I), the cyclic group is a cycloalkyl,heterocycloalkyl, cycloalkenyl, heterocycloalkenyl, aryl, heteroaryl,alkaryl, alkylheteroaryl, aralkyl or heteroaralkyl group.
 35. Theprocess of claim 34 wherein in metallocene procatalyst (I), ligand(Cp¹R_(m) ¹) is unsubstituted cyclopentadienyl, ligand (Cp²R_(p) ²) issubstituted or unsubstituted indenyl or fluorenyl, M¹ is zirconium, R⁴and R⁵ each is phenyl and each ligand X is chlorine.
 36. In a processfor polymerizing at least one olefin to provide a polyolefin employing,as polymerization catalyst, the product obtained by combining ametallocene procatalyst possessing at least one non-cyclopentadienylligand X coordinated to its transition metal with an aluminoxanecocatalyst, wherein the improvement comprises employing a differentcation-generating cocatalyst in place of part or all of said aluminoxanecocatalyst, said different cation-generating cocatalyst comprising: ametal- and/or metalloid-containing first component capable of exchangingone or more ligands X up to the full number thereof with, independently,a hydrogen atom, a carbohydryl group containing up to about 20 carbonatoms or an oxyhydrocarbyl group containing up to 20 carbon atoms; aneutral metal- and/or metalloid-containing second component having atleast one aryl group possessing at least one electron-withdrawingsubstituent; and, an anionic metal-containing third component having atleast one aryl group possessing at least one electron-withdrawingsubstituent alone or in combination with an anionic metalloid-containingthird component having at least one aryl group possessing at least oneelectron-withdrawing substituent.
 37. The process of claim 36 wherein inthe different cation-generating cocatalyst, the first component is analuminum compound, the second component is a borane compound and thethird component is a metal borate compound.
 38. The process of claim 37wherein the aluminum compound is a trialkylaluminum or dialkylaluminumhydride, the borane compound is a tris(haloaryl)borane and the metalborate compound is an alkali metal-, alkaline earth metal-, ortransition metal-tetrakis(haloaryl)borate.
 39. The process of claim 38wherein the aluminum compound is a trialkylaluminum, the borane compoundis a tris(halophenyl)borane and the metal borate compound is an alkalimetal tetrakis(halophenyl)borate.
 40. The process of claim 37 whereinthe aluminum compound is at least one of trimethylaluminum,triethylaluminum, tri(n-propyl)aluminum, triisopropylaluminum,tri(n-butyl)aluminum, tri(n-propyl)aluminum, triisobutylaluminum,tri(n-hexyl)aluminum, tri(n-octyl)aluminum, dimethyaluminum hydride,diethylaluminum hydride, diisopropylaluminum hydride,di(n-propyl)aluminum hydride, diisobutylaluminum hydride,di(n-butyl)aluminum hydride, dimethylaluminum ethoxide,di(n-propyl)aluminum ethoxide, diisobutylaluminum ethoxide ordi(n-butyl)aluminum ethoxide, the borane compound is at least one oftris(pentafluorophenyl)borane, tris(methoxyphenyl)borane,tris(trifluoromethylphenyl)borane, tris(3,5-di[trifluoromethyl]phenyl)borane, tris(tetrafluoroxylyl)borane or tris(tetrafluoro-o-tolyl)boraneand the metal borate compound is at least one of lithiumtetrakis(pentafluorophenyl)borate, lithiumtetrakis(trifluoromethylphenyl)borate, lithium tetrakis(3,5-di[trifluoromethyl]phenyl)borate, sodium tetrakis(pentafluorophenyl)borate, potassium tetrakis(pentafluorophenyl)borate,magnesium tetrakis(pentafluorophenyl)borate, titaniumtetrakis(pentafluorophenyl)borate or tin tetrakis(pentafluorophenyl)borate.
 41. The process of claim 36 wherein themetallocene procatalyst is combined with the components of the differentcation-generating cocatalyst in the presence of olefin.
 42. The processof claim 36 wherein the olefin is ethylene, propylene or a mixture ofethylene and propylene.